Centralizer for drill steels



,1. F. MocK' CENTRALIZER FOR DRILL STEELS -Oct. -4, 1 27. 1,644,026

Filed Oct. 8, 1926 Patented Oct. 4, 1927.

v UNITED STATES 1,644,026 PATENT OFFICE.

JOHN F. MOCK, OF PHILLIPSBURG, NEl/V JERSEY, ASSIGNOR T INGERSOLL-RAND COM- PANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

CENTRALIZER FOR DRILL STEELS.

Application filed October 8, 1926.

This invention relates to rock drills, but more particularly to a centralizer for the working implement of rock drills of the hammer type.

One object of the invention is to guide and support the overhanging portion of a working implement so that in starting a drill hole the bit of the working implement will be held in axial alignment with the fool:

drill. v

Another object is to render the centralizer readily attachable and removable to and from the roclr drill shell.

Other objects will appear hereinafter and to all of these ends the invention consists of the combinations of elements and features of construction, substantially as hereinafter described and more particularly pointed out in the appended claims and illustrated in the accompanying drawings, in whi.ch

Figure 1 is an elevation of the front end of a rock drill and its shell illustrating the manner in which the centralizer supports and guides the working implement,

Figure 2 is a transverse View taken through Figure 1 on the line 22 looking in the direction of the arrows,

Figure3 is a side elevation of the central- 3 izer, and

Figure 4 is a plan view, partly in section, taken through Figure 3 on the line lllooking' in the direction of the arrows.

Referring more particularly to the drawings, A represents a shell of any suitable type having a conical projection B whereby the shell may be secured to a column. or other suitable support for holding the shell in tired position with respect to the working surface, such as the roclr designated by C,

In the present instance, only'ithe front end of a front head D is shown in the drawings for the sake of simplicity of'illustration, but it is to be understood that other elements (not shown) of the rock drill may cooperate slidably with the guideways E of the shell A in a well known manner. A working implement illustrated in this instance as drill steel extends with its rearward end into the front head D to receive the blows of the reciprocatory hammer piston (not urn) of the drill. v

in certain drilling operations, it is at times found difiicult to maintain the drill bit coaxial with the rock drill, particularly when the rock drill lies in an inclined posi- Serial No. 140,341.

tion. After a certain period of usage, wear is caused in the chuck parts of the rock drill and as a resultthe bit end of the drill steel tends to incline from the axis of the rock drill. lVhen operating under these conditions, the drill bit will swing about the desired axi in starting a new drill hole and as a result the hole will incline from the intended course. Frequently, these conditions are not detected until a certain depth has been drilled and until drill steels of greater length have been substituted for the starting drill. If then the position of the drill is not changed to coincide with the course of the drill hole. the drill steel willbind in the drill. hole and will greatly hinder the rotation of the drill steel. As a result, the drilling efliciencv will be considerably lowered, the drill bit will require more frequent sharpening, and it will also be more difficult to maintain the gauge of the drill bit than would be the case if the drill bit could be maintained in axial alignment with the drill. i y

The present invention aimsv to eliminate the foregoing described objectionable features and to this end is provided a centralizer designated generally by G. The centralizer in this instance comprises two pairs of arms designated by H and J. Through the upper ends of these arms extends in this instance a bolt K which. acts as a pivot for the arms and is. provided with a nut L whereby the arms may be clamped in operative position with respect to each other. The arms H and J in this instance are arranged in pairs, that is, one arm H and one arm J are arranged on each side of the pivotal point of the centralizer.

At the lowermost ends of the arms H and J are formed lateral. extensions 0 and P which extend slidably into the guideways E of the shell A wherewith they cooperate to hold the centralizer G in operative position.

Beneath the extensions 0 and P are formed shoulders which bear against surfaces R of the shell A.

In order to at all times hold the shoulders Q. in frictional engagement with the surfaces R, set screws S are in this instance threaded throughone pair of arms H and J to bear against inner surfaces T of theopposed arms H and J. In this way after the centralizer has been placed in guiding position in the shell, the opposed arms may be quickly spread by merely turning the set screws S to a point where the desired frictional contact between the shoulders Q and the surfaces It may be obtained.

In the inner surfaces T of the arms H and J are formed recesses U having reduced cylindrical portions V at one end. The walls of the recesses U in this instance cousist of two arcuate surfaces W and a flat surface X connecting the surfaces il The enlarged portion of the recess U is extended rearwardly or beneath the reduced portion V to form dove-tails Y.

Disposed slidably within the recesses U are bushing sections Z, the outer surfaces of enlarged intermediate portions 5 of which are of a shape to conform to the recesses U. Accordingly, these bushing sections Z are also provided with flat surface 0 which cooperate with the flat surfaces ii of the arms for preventing relative rotative move ment between the bush ng se-tioiris and, tne arms H and. (l. The c. and part the bushings are thus also of (low-tail shape at their ends to engage the dove-tails Y of the arms H and J for locl i. the bushings to the arms. I

lVithin the bushing sections Z are fori'ned semi-circular recesses (Z which cooperate to form a continuous guiding surface for the drill steel F which they encircle.

In assembling the centralizer a bushing section Z may be disposed in the recesses U of the arms H and J, it being understood that one of each of the arms H and J be arranged on opposite sides of the pivotal. point. After the arms of the bushing sections have been thus assembled the opposed pairs of arms may be arranged in their assembled positions to receive the bolt K. Thereafter the nut L may be screwed. on the end of the bolt K and the centraiizer may be disposed in the rock drill shell and the drill steel may be inserted through the centralizer to extend into the front head D as illustrated in Figure 1. In case the drill steel F be of the type in which collars. win or other equivalent means preventing ejection of the drill steel om the front head. the drill steel may first be inserted in the front head and the eent-ralizer may then be swung open and placed around the drill steel before attaching the said centralizer to the shell A.

After the eentralizer has been disposed in the guideways E of the shell. the set screws S may be screwed in the direction necessary to force the shoulders Q of the arms l; and J firmly against the surfaces R to clamp the centralizer in iii-(ed position. or, if found desirable, the set screws may be screwed down only a suliicient distance to prevent the con tralizer from being moved out of position by the shocks and vibration set up by the drill.

7 are provided for If the centralizer is only clamped lightly to the rock drill shell, it will not be necessary to again remove the same before chang ing the drill steel since the front head upon approaching the front end of the shell will then push the centralizer out of the guideways E and the centralizer may be removed from the vicinity of the drill hole without stopping the drilling operations.

The foregoing described centralizer has been found to be unusually durable and efiicient in operation. It maybe quickly disposed in operative position or removed from the shell and has the added advantages of the renewable guiding and wearing bushings which may be quickly replaced without the aid or necessity of special tools or equipment.

1 claim:

17 A centralizer for drill steels, comprisng a plurality of arms, a pivot connecting he arms, means disposed slidably in the arms to engage the arms in pairs for preventing relative pivotal movement between arms on the same side of the centralizer, said means being adapted to encircle a working ii'nplement, and extensions on the arms adapted to cooperate slidably with the guideways of a rock drill shell.

it centralizer for drill steels, comprising a plurality of arms, said arms being .arranged in pairs forming opposite sides of the centralizer, a pivot connecting the arms, means interlocking with arms lying on-the same side of the pivot encircling a working in'iplement, means on said means interlockingly engaging the arms, lateral extensions on the arms adaptedto cooperate slidably "ltl guideways of a rock drill shell. and means for spreading the opposed arms to hold the extensions in frictional engagement with such guideways. V

3. A centralizer for drill steels, comprising a plurality of arms, said arms being arranged in pairs forming opposite sides of the centralizer, bushings in each pair of arms encircling a working implement, said bushings and said arms having interlocking aortlons to retain the bushings in the arms,

JOHN F. MOCK. 

